I came across the macro with-eval-after-load when trying to install persp-mode from here. But I am unable to find the macro inside Emacs and/or on Google. Where is it defined? Is it part of standard Emacs Lisp?
From etc/NEWS:
* Lisp Changes in Emacs 24.4
...
** New macro `with-eval-after-load'.
This is like the old `eval-after-load', but better behaved.
Emacs 24.4 was released on 20th October 2014.
eval-after-load is considered ill-behaved because it is a function, not a macro, and thus requires the code inside it to be quoted, which means that it cannot be byte-compiled. It also accepts only one form, so if you have more than one, you need to use progn. For example:
(eval-after-load "foo"
'(progn
(setq foo 42)
(setq bar 17)))
The equivalent version with with-eval-after-load would be:
(with-eval-after-load "foo"
(setq foo 42)
(setq bar 17))
As noted by Clément in a comment, one disadvantage of with-eval-after-load is that you cannot rely on macros defined in the module in question, while with eval-after-load you can be sure that such macros are defined and available to use. This was discussed on emacs-devel.
Related
I'm trying to write an emacs LISP function to un-indent the region
(rigidly). I can pass prefix arguments to indent-code-rigidly or
indent-rigidly or indent-region and they all work fine, but I don't
want to always have to pass a negative prefix argument to shift things
left.
My current code is as below but it seems to do nothing:
(defun undent ()
"un-indent rigidly."
(interactive)
(list
(setq fline (line-number-at-pos (region-beginning)))
(setq lline (line-number-at-pos (region-end)))
(setq curIndent (current-indentation))
;;(indent-rigidly fline lline (- curIndent 1))
(indent-region fline lline 2)
;;(message "%d %d" curIndent (- curIndent 1))
)
)
I gather that (current-indentation) won't get me the indentation of the first line
of the region, but of the first line following the region (so a second quesiton is
how to get that!). But even when I just use a constant for the column (as shown,
I don't see this function do any change.
Though if I uncomment the (message) call, it displays reasonable numbers.
GNU Emacs 24.3.1, on Ubuntu. And in case it matters, I use
(setq-default indent-tabs-mode nil) and (cua-mode).
I must be missing something obvious... ?
All of what Tim X said is true, but if you just need something that works, or an example to show you what direction to take your own code, I think you're looking for something like this:
(defun unindent-rigidly (start end arg &optional interactive)
"As `indent-rigidly', but reversed."
(interactive "r\np\np")
(indent-rigidly start end (- arg) interactive))
All this does is call indent-rigidly with an appropriately transformed prefix argument. If you call this with a prefix argument n, it will act as if you had called indent-rigidly with the argument -n. If you omit the prefix argument, it will behave as if you called indent-rigidly with the argument -1 (instead of going into indent-rigidly's interactive mode).
There are a number of problems with your function, including some vary
fundamental elisp requirements. Highly recommend reading the Emacs Lisp
Reference Manual (bundled with emacs). If you are new to programming and lisp,
you may also find An Introduction to Emacs Lisp useful (also bundled with
Emacs).
A few things to read about which will probably help
Read the section on the command loop from the elisp reference. In particular,
look at the node which describes how to define a new command and the use of
'interactive', which you will need if you want to bind your function to a key
or call it with M-x.
Read the section on variables from the lisp reference
and understand variable scope (local v global). Look at using 'let' rather
than 'setq' and what the difference is.
Read the section on 'positions' in the elisp reference. In particular, look at
'save-excursion' and 'save-restriction'. Understanding how to define and use
the region is also important.
It isn't clear if your writing this function just as a learning exercise or
not. However, just in case you are doing it because it is something you need to
do rather than just something to learn elisp, be sure to go through the Emacs
manual and index. What you appear to need is a common and fairly well supported
requirement. It can get a little complicated if programming modes are involved
(as opposed to plain text). However, with emacs, if what you need seems like
something which would be a common requirement, you can be fairly confident it is
already there - you just need to find it (which can be a challenge at first).
A common convention is for functions/commands to be defined which act 'in
reverse' when supplied with a negative or universal argument. Any command which
has this ability can also be called as a function in elisp code with the
argument necessary to get that behaviour, so understanding the inter-play
between commands, functions and calling conventions is important.
I get this message when starting SLIME:
; loading #P"d:/lisp/slime-2.12/swank-loader.lisp"
STYLE-WARNING: redefining EMACS-INSPECT (#<SB-PCL:SYSTEM-CLASS T>) in DEFMETHOD
The REPL works normal.
I am totally new to EMACS and SLIME and I'd like to know what does this mean and how to fix it.
I use Windows 8 (64-bit), GNU Emacs 25.0.50.1 (x86_64-w64-mingw32), SLIME 2.12, and SBCL 1.2.7
I addressed folks in GitHub and jackcarrozzo replied
with this post:
Good question - it took a bit of spelunking to find a full answer. The short answer is that emacs-inspect stores handlers for inspecting objects; when a particular object is inspected, the relevant generic function (based on type) will match and be evaluated. From http://lisp-book.org/contents/chslime.pdf page 16, you can run this to see the currently-attached generics:
M-. swank-backend:emacs-inspect
That pdf also describes creating your own inspector as well as additional features that look pretty cool.
Regarding your second point: lots of stuff gets printed to the slime-events buffer; unless you're having a slime-specific issue, you probably don't need to even have it open in a window. Warnings and so forth relevant to your code and interactions will come out either directly in the REPL, in the inferior-lisp buffer, or in one of a few other buffers that emacs/slime will auto-open for you when needed.
CL-USER> (use-package :elk)
; Evaluation aborted on #<SB-KERNEL:SIMPLE-PACKAGE-ERROR "The name ~S does not designate any package." {1002C9D683}>.
CL-USER> (defun moose (a) (+ a 7))
MOOSE
CL-USER> (defun moose (a) (+ a 8))
STYLE-WARNING: redefining COMMON-LISP-USER::MOOSE in DEFUN
MOOSE
CL-USER>
So, in summary: don't worry about it. Slime makes interfacing Common Lisp in emacs simple, and it does a great job of staying out of the way. Slime does admittedly have a ton of features but it doesn't force you to use them. Note to self: I should really get around to learning them some day...
Emacs 23.2 in emacs-starter-kit v1 has C-x C-i (or ido-imenu) (similar to Sublime Text's Cmd+R). Emacs24 in emacs-starter-kit v2 lacks this function. I found this github issue and a fix, which try to recreate the functionality. While this ido-imenu works in elisp-mode, it stopped working in ruby-mode. I get:
imenu--make-index-alist: No items suitable for an index found in this buffer
Has anyone figured out how to get this to work?
Why was this taken out of Emacs24?
Is there a new replacement for this function?
Since the function is part of ESK (as opposed to something budled with Emacs) you'd probably do best to report the bug upstream. On a related note ESK main competitor Emacs Prelude offers the same functionality (bound to C-c i by default) and it seems to be working fine with ruby-mode in Emacs 24. Here you can find more on ido-imenu.
So I finally figured it out, after reading the Defining an Imenu Menu for a Mode section on emacs-wiki again.
Short answer: you need to add this bit to your customization. Feel free to add more types to the list (I am happy with just methods).
(add-hook 'ruby-mode-hook
(lambda ()
(set (make-local-variable imenu-generic-expression)
'(("Methods" "^\\( *\\(def\\) +.+\\)" 1)
))))
Longer answer: I first tried to define a ruby-imenu-generic-expression function and set that to imenu-generic-expression by using the ruby-mode-hook:
(defvar ruby-imenu-generic-expression
'(("Methods" "^\\( *\\(def\\) +.+\\)" 1))
"The imenu regex to parse an outline of the ruby file")
(defun ruby-set-imenu-generic-expression ()
(make-local-variable 'imenu-generic-expression)
(make-local-variable 'imenu-create-index-function)
(setq imenu-create-index-function 'imenu-default-create-index-function)
(setq imenu-generic-expression ruby-imenu-generic-expression))
(add-hook 'ruby-mode-hook 'ruby-set-imenu-generic-expression)
This however did not work (I would get the same error as before). More reading of the Defining an Imenu Menu for a Mode section showed me the way. Now, I'm not an elisp expert, so here's my hypothesis: basically, the above method works for modes where the
major mode supports a buffer local copy of the “real” variable, ‘imenu-generic-expression’. If your mode doesn’t do it, you will have to rely on a hook.
The example for foo-mode made it clear how to do it for ruby-mode. So it appears that ruby-mode does not have a buffer-local copy of the real imenu-generic-expression variable. I still can't explain why it worked in Emacs 23.2 (with ESK v1) but does not on Emacs24, but hey at least I found a working solution.
I want to write an Emacs Lisp function that will turn on flyspell-mode regardless of the current state of the mode. Function flyspell-mode-on is deprecated. The documentation suggests that a positive prefix argument will turn flyspell-mode, but unfortunately running
(flyspell-mode 1)
results in an error message:
Wrong number of arguments: (lambda (flyspell-mode 1)), 0
If I could figure out how to call flyspell-mode with a prefix argument, I believe I could solve this problem.
The most relevant section I can find in the Emacs Lisp manual is the section entitled "Interactive Call", which describes such commands as call-interactively. This is emphatically not what I want.
(The ultimate problem I am trying to solve is to create a mode hook that turns on the mode regardless of its current state.)
N.B. The title of the question emacs lisp call function with prefix argument programmatically makes it appear to be related, but that question was asking about how to create an interactive command, and the issue was ultimately resolved by using call-interactively.
EDIT: This question is moot; I have found an alternate solution to my original problem:
(add-hook 'text-mode-hook
(function (lambda ()
(require 'flyspell)
(if flyspell-mode nil (flyspell-mode)))))
But I would still like to know how to call an Emacs Lisp function with a prefix argument, from another Emacs Lisp function, with nothing interactive.
UPDATE: Perhaps I should have asked why I was getting that error message...
It looks like your version of Flyspell mode does not follow the minor mode conventions, which require that you can turn on a minor mode with (name-of-mode t) or any positive prefix argument, turn it off with (name-of-mode 0) any negative prefix argument, and toggle it with (name-of-mode nil).
If you have the latest version of Flyspell, a bug report might be in order. I have the version shipped with GNU Emacs 23.2 on my machine, and it respects the convention. My version also defines two functions turn-on-flyspell and turn-off-flyspell, both trivial wrappers around flyspell-mode; functions with such names are common, but not official conventions. The functions flyspell-mode-on and flyspell-mode-off are apparently intended for internal use.
As a general matter, commands read the current prefix argument from the current-prefix-arg variable. Don't confuse that with prefix-arg, which is the value for the next command (only a few commands like universal-argument touch this variable). Thus, if you need to pass a prefix argument when calling a function, bind or set current-prefix-arg.
(let ((current-prefix-arg t))
(flyspell-mode))
If you are not calling a function interactively, then the (interactive) declaration is not used to obtain the arguments.
In the vast majority of cases, you do not need to worry about whether an argument can be a "prefix argument" for non-interactive calls; just check the function documentation, and pass the value you need for whatever it is you want to do.
If for some reason you do need to replicate sending a prefix argument in a non-interactive context, you will need to check that function's (interactive) declaration and determine exactly how it is using that argument, and ensure that you replicate that behaviour for the argument you do pass.
For full details, see:
C-hf interactive RET
M-: (info "(elisp) Prefix Command Arguments") RET
In more complex cases where the function changes its behaviour based on the current-prefix-arg variable, you may be able to set that variable directly.
(let ((current-prefix-arg '(4)))
(foo current-prefix-arg))
I can think of this.. Should be more better
(call-interactively (lambda ()
(interactive)
(flyspell-mode '(4))))
UPDATE:
I can run this directly.. what am i missing from the question.?
(flyspell-mode '(4))
EDITED: Removed quote for lambda expression (I added this note because SX forces an edit to be at least six characters long, so this can be deleted).
FWIW, the `flyspell-mode' function has accepted an argument (as in "(flyspell-mode 1)") at least since Emacs-21, so I don't know how you got that error.
But while I'm here, I might as well point out that (add-hook 'text-mode-hook 'flyspell-mode) has changed meaning in Emacs-24: instead of meaning "toggle flyspell-mode in text modes" it will now mean "enable flyspell-mode in text modes". It's a backward-incompatible change, but I believe it will fix more latent bugs than it will introduce.
See my comment for the fix to the source of your problem. As for the answer to your question, the way the prefix arg is turned into some kind of Lisp argument depends on the interactive spec, so the only way to do it reliably (i.e. without prior knowledge such as the fact that it's a minor mode function) is to call the function interactively:
(let ((current-prefix-arg '(4)))
(call-interactively 'flyspell-mode))
I'm not Emacs and Elisp master (yet ;)) but I think in this case you may use Ctrl-u 1 Alt-x flyspell-mode.
I am moving to Emacs to work on Clojure/Lisp.
What is all the information I need to setup on Emacs to be able to do the following?
automatic matching/generation of corresponding closing brackets
autoindent Lisp/Clojure style, not C++/Java style
Syntax highlighting
Invoking REPL
To be able to load a part of code from file into the REPL and evaluate it.
It would be great if I could also get the list of commands to get these things after setting things up on Emacs.
[Edit from non-author: this is from 2010, and the process has been significantly simplified since May 2011. I'll add a post to this answer with my setup notes as of Feb 2012.]
You'll need to put together a few pieces: Emacs, SLIME (which works perfectly well with Clojure -- see swank-clojure), swank-clojure (the Clojure implementation of SLIME's server counterpart), clojure-mode, Paredit and, of course, the Clojure jar for a start, then perhaps some extras among which Leiningen would perhaps be the most notable. Once you do set it all up, you'll have -- within Emacs -- all the workflow / editing features you mention in the question.
Basic setup:
The following are to great tutorials which describe how to set all of this up; there's more on the Web, but some of the others are quite outdated, whereas these two seem to be ok for now:
in which are found tricks of the trade concerning clojure authorship post on Phil Hagelberg's blog; Phil maintains swank-clojure and clojure-mode, as well as a package called the Emacs Starter Kit which is something any newcomer to the Emacs world would be well-advised to have a look at. These instructions seem to have been brought up to date with recent changes to the infrastructure; in case of doubt, look for additional information on Clojure's Google group.
Setting up Clojure, Incanter, Emacs, Slime, Swank, and Paredit post on the blog of the Incanter project. Incanter is a fascinating package providing an R-like DSL for statistical computations embedded right into Clojure. This post will be useful even if you don't plan on using -- or even installing -- Incanter.
Putting it all to work:
Once you set up all of this stuff, you could try and start using it right away, but I would strongly advise you to do the following:
Have a look at SLIME's manual -- it's included in the sources and is actually very readable. Also, there's absolutely no reason why you should read the whole 50-page monster manual; just have a look around to see what features are available.
Note: the autodoc feature of SLIME as found in the latest upstream sources is incompatible with swank-clojure -- this problem won't come up if you follow Phil Hagelberg's recommendation to use the ELPA version (see his aforementioned blog post for an explanation) or simply leave autodoc off (which is the default state of things). The latter option has some added appeal in that you can still use the latest SLIME with Common Lisp, in case you use that as well.
Have a look at the docs for paredit. There are two ways to go about this: (1) look at the source -- there's a huge amount of comments at the top of the file which contain all the information you're likely to need; (2) type C-h m in Emacs while paredit-mode is active -- a buffer will pop up with information on the current major mode followed by information on all active minor modes (paredit is one of those).
Update: I've just found this cool set of notes on Paredit by Phil Hagelberg... That's a link to a text file, I remember seeing a nice set of slides with this information somewhere, but can't seem to find it now. Anyway, it is a nice summary of how it works. Definitely take a look at it, I can't live without Paredit now and this file should make it very easy to start using it, I believe. :-)
In fact, the C-h m combination will tell you about all keybindings active at the SLIME REPL, in clojure-mode (you'll want to remember C-c C-k for sending the current buffer off for compilation) and indeed in any Emacs buffer.
As for loading the code from a file and then experimenting with it at the REPL: use the aforementioned C-c C-k combination to compile the current buffer, then use or require its namespace at the REPL. Next, experiment away.
Final notes:
Be prepared to have to tweak things for a while before it all clicks. There's a lot of tools involved and their interactions are mostly fairly smooth, but not to the point where it would be safe to assume you won't have to make some adjustments initially.
Finally, here's a bit of code I keep in .emacs which you won't find elsewhere (although it's based on a cool function by Phil Hagelberg). I alternate between starting my swank instances with lein swank (one of the cooler features of Leiningen) and using the clojure-project function as found below to start the whole thing from within Emacs. I've done my best to make the latter produce an environment closely matching that provided by lein swank. Oh, and if you just want a REPL in Emacs for a quick and dirty experiment, then with the correct setup you should be able to use M-x slime directly.
(setq clojure-project-extra-classpaths
'(
; "deps/"
"src/"
"classes/"
"test/"
))
(setq clojure-project-jar-classpaths
'(
; "deps/"
"lib/"
))
(defun find-clojure-project-jars (path)
(apply #'append
(mapcar (lambda (d)
(loop for jar in (remove-if (lambda (f) (member f '("." "..")))
(directory-files d t))
collect jar into jars
finally return jars))
(remove-if-not #'file-exists-p
clojure-project-jar-classpaths))))
(defun find-clojure-jar (jars)
(let ((candidates
(remove-if-not
(lambda (jar)
(string-match-p "clojure\\([0-9.-]+\\(SNAPSHOT|MASTER\\)?\\)?\\.jar$" jar))
jars)))
(if candidates
(car candidates)
(expand-file-name "~/.clojure/clojure.jar"))))
(defun find-clojure-contrib-jar (jars)
(let ((candidates
(remove-if-not
(lambda (jar)
(string-match-p "clojure-contrib\\([0-9.-]+\\(SNAPSHOT|MASTER\\)?\\)?\\.jar$" jar))
jars)))
(if candidates
(car candidates)
(expand-file-name "~/.clojure/clojure-contrib.jar"))))
;;; original due to Phil Hagelberg
;;; (see `Best practices for Slime with Clojure' thread on Clojure Google Group)
(defun clojure-project (path)
"Sets up classpaths for a clojure project and starts a new SLIME session.
Kills existing SLIME session, if any."
(interactive (list (ido-read-directory-name
"Project root:"
(locate-dominating-file default-directory "pom.xml"))))
(when (get-buffer "*inferior-lisp*")
(kill-buffer "*inferior-lisp*"))
(cd path)
;; I'm not sure if I want to mkdir; doing that would be a problem
;; if I wanted to open e.g. clojure or clojure-contrib as a project
;; (both lack "deps/")
; (mapcar (lambda (d) (mkdir d t)) '("deps" "src" "classes" "test"))
(let* ((jars (find-clojure-project-jars path))
(clojure-jar (find-clojure-jar jars))
(clojure-contrib-jar (find-clojure-contrib-jar jars)))
(setq swank-clojure-binary nil
;; swank-clojure-jar-path (expand-file-name "~/.clojure/clojure.jar")
swank-clojure-jar-path clojure-jar
swank-clojure-extra-classpaths
(cons clojure-contrib-jar
(append (mapcar (lambda (d) (expand-file-name d path))
clojure-project-extra-classpaths)
(find-clojure-project-jars path)))
swank-clojure-extra-vm-args
(list (format "-Dclojure.compile.path=%s"
(expand-file-name "classes/" path)))
slime-lisp-implementations
(cons `(clojure ,(swank-clojure-cmd) :init swank-clojure-init)
(remove-if #'(lambda (x) (eq (car x) 'clojure))
slime-lisp-implementations))))
(slime))
There is one more excelent tutorial:
http://www.braveclojure.com/basic-emacs/ (1st part)
http://www.braveclojure.com/using-emacs-with-clojure/ (2nd part)
In 30 to 45 minutes one can have everything setup from scratch.
The tutorial does not assumes any prior knowladge of Emacs (and Clojure too - in earlier posts there is a nice intro to Clojure).
The Emacs Starter kit has gotten great reviews for getting started with Clojure:
To answer only the swank part of your question:
Leiningen is a really easy way of setting up swank with the correct classpath and get it connected to Emacs.
A great video is here: http://vimeo.com/channels/fulldisclojure#8934942
Here is an example of a project.clj file that
(defproject project "0.1"
:dependencies [[org.clojure/clojure
"1.1.0-master-SNAPSHOT"]
[org.clojure/clojure-contrib
"1.0-SNAPSHOT"]]
:dev-dependencies [[leiningen/lein-swank "1.1.0"]]
:main my.project.main)
then run:
lein swank
and from Emacs:
alt-x slime-connect
Clojure with Emacs on Clojure Documentation can be useful too.
CIDER (Clojure Interactive
Development Environment) must be mentioned here.
It’ll cover most of what you’re looking for. It includes:
interactive REPL
debugging
test running
code navigation
documentation lookup
lots more
In addition to CIDER, there are some other essential and nice-to-have
add-ons for clojure development, which I’ll try to group respectively
(and subjectively):
Essentials
smartparens – parentheses
pairing, manipulation, navigation (or
parinfer if you prefer)
clj-refactor –-
has a couple amazing features, like auto-adding/compiling namepaces
(it may be incorporated into CIDER soon)
clojure-mode –
font-lock, indentation, navigation
company – text completion
framework (or choose another auto-completer)
rainbow delimeters –
highlights/colorizes delimiters such as parentheses, brackets or
braces according to their depth
flycheck – on-the-fly syntax
checking extension
flycheck-clj-kondo –
integration for clj-kondo
Niceties
clojure-snippets –
tab-expandable shortcuts to longer code chunks
dumb-jump – jump to
definitions
which-key – displays
available keybindings in popup
highlight parentheses –
highlight surrounding parentheses
crux – a Collection of
Ridiculously Useful eXtensions for Emacs
comment-dwim-2 –
replacement for Emacs’ built-in comment-dwim
General Essentials (for any language)
magit – git porcelain inside Emacs
projectile – project mgmt
for finding files, searching, etc
helm – incremental completion
and selection narrowing framework (or
swiper)
Other Resources
If you’re looking for a setup that already has done most/all of this
work for you, a couple options are:
prelude
spacemacs